Electromagnetic Diffraction

 

Diffraction, the spreading of waves around obstacles.Diffraction takes place with sound; with electromagnetic radiation, such as light, X-rays, and gamma rays; and with very small moving particles such as atoms, neutrons, and electrons, which show wavelike properties.One consequence of diffraction is that sharp shadows are not produced. The phenomenon is the result of interference (i.e., when. Keywords: Nonlinear wave equation, diffraction, electromagnetic tunneling, semiconductor plasma, impact ionization, power limiting, stiff differential.

Diffraction Theory of Electromagnetic Waves

Abstract

It has been shown by Larmor, Kottler and others that the classical method of calculating diffraction from the Kirchhoff formula in terms of a scalar light function cannot be applied directly to the electromagnetic field since it takes into account neither the vector character of the field nor the effect of charges along the contour of the opening. The field equations are integrated directly by means of a vector analog of Green's theorem. The results are applied to the calculation of diffraction of electromagnetic waves from a rectangular slit in a screen of infinite conductivity. The results are compared with an exact solution obtained recently by Morse and Rubenstein.


Publication:
Pub Date:
July 1939
DOI:
10.1103/PhysRev.56.99
Bibcode:
1939PhRv...56...99S
кандидата физико-математических наукУЧЕНАЯ СТЕПЕНЬ
1995ГОД ЗАЩИТЫ
01.04.03КОД ВАК РФ
Автореферат диссертациина тему 'Diffraction of electromagnetic waves on the systems of cylindrical gratings, dielectrical layer and screen'

REPUBLIC OF GEORGIA' TBILISI STATE UNIVERSITY

Licensed as oanascript

RoaaaG. Kevanishvlll

DIFFRACTION OF ELECTROMAGNETIC WAVES ON THE SYSTEMS OF CYLINDRICAL GRATINGS, DIKLECTRICAL LAYER AND SCREEN

Speciality 01.02.03 - radiophysica

ABSTRACT

of the dissertation for receiving the scientific degree of candidate of physical and mathematical sciences

TBILISI - 1995

Tthe work is made In GeorgIna Technical Univesity

Guide of science - Doctor of physical and aathenatlcal

sciences, Assistant Professor •

F.Q.BOGDANOV _ (Gni)

Official opponents: Doctor of physical and mathematical sciences, O.P.TSAaAHKlStiyiM (TSU),

... i' ' Candidate of physical and aathenati-

-;.- . cal sciences, Assistant Professor y, , Z.I.B1KMASHV1M (T80J • . ; -

'The dofence of the dissertation will take plaoe on 1995 at 1« o'clock In the sitting of the Tbilisi State University's scientific-attestation council 01.02 H 1-6 C Cavchavadne av. 3, BPA, 3800ZB,Tbilisi).

You may become acquainted With dissertation In this fundumental library of Tbilisi State University.

Abstract ls'dlstrlbutod on *'r 1995

Sclenilo-Attestatlon .tj-'-i' .5 ■

Electromagnetic waves diffraction

; Coucil'a nclentific . • ', i;' ?

Electromagnetic Diffraction

staretnry. Professor ; ' , D.I.ALADABBVILI ;.

V ; ; ' j . GEHKRAli raAKACTErilB', ICS OF THK WOKK

■ ÍSÍy?!^? the theyo„ Last tirao in pract ca.l i adiophy-D.caandrnJiotechnl r-3 together wi th the simple gra jinga tho moro and more attention of invostigatora in excite 1 by the ' complicated eleot.rodyiiamic structures, including gratings, ■dielectrical layers; screens and Oihera. Tuey are 'iseii in resonators, antenna radons, passive retranalutora, phase t-rnlngH, Polarization transformers, artifical dielectrics, SRF integral schemes, quantum . enerators and so on. /•The theoretical Investigations >t tho complicated electro-dynamic ¿yaterna aro carried by the methods, developed for tho unit gratings. Hut tha moat, of these methods are approximate, therefore the received results have often the limited area

* appliement.'At the saine time the deep (rigorous; investigation of complicated ny stems !'■ necehaary to . improve the present and to create the new itchnics. That is why the works in thi s direction are very actual ,fcr today.

' J??? purpose of work is ■ investigation of diffraction of the plane wavésoñ complicated eleotrodynaniii: structures consisting of circle-cylindrical aratinan, dielectrical layer and

• screen:.

Determination of the qu mtity of the reflection (passing) 'coefficients „by the main waves jnd of the oth t. phj sical characteristics of the system, and to limits, except wicieuaed ón radiuses of cylinders and periods oi gratings are applied.

As a method of invii^tigatioji._iqLiL^L<}__the projectional me-.thod which lets i o transform the'aystem'óí su.araatory equations of the tank to the infinite a/stem of che linear n«->u-JjomoHene.ous algebraic eq—vtio;.a of the second order, which solution may be realized by ECU by the reduction method., ? In the work , wera , supplied and rigorously nolved; the 1 following problems: -- , -v .4'■

'i,- 1) Difiract.on of el >ctromajjnetic'wav^s on . the ayateau of

gratinga and dielectricnl layer; ■■ ■ ' ' ,

, ,* ?) Diffraction of ej-ystromagnetic waves on tlie ay stems pf Bratinaa and screen; ■ ' .

3) Diffraction of oleotromaunotia'waves on, the Hrating of dielectrical cylinders,in the dieléctrica; layer.

In the dissertation supplement tho calculating programes 1 . of tiiiJ ikaia. diffraction characteristics of all investigated n>aterís are/introduced. . . V . .-• '

Inn anallsi3 of l¡.»J-ee .grnfleal . material allowed to find ! out some special properties of. complicated eléctr<>dinamic structures, including tha following»: / '. '

,«) Tha at:tem of tha /.ratings and the ' dielectrical laye', ' la tho semi trail apar on t, rezoúátor will Íííso,' in comparison Mith the insulator u?a'/;iilff,! fokal proporti i£¡. 'filó passing Coefficient of tho aiotedi is equal- to the prtduct of uhe grn-iint. pasaiog cooff ioient (in the case of 'tho layer presence) nnd the layer ltttelf, and tho■reflection coefficient equals ta'tiioif sua,-.. •..... , i - 1 - f

• ■ 14 - . : . - j.

l>) The siirtcm of the F, 'atins and the screen in' tl.e effective reflectionary grating and declares the properties of the ph(i3eturni».ir and of the harmonica transformers,' and in the enerjysaver; ';'-.:

c) The diel .-ctrical gratiin in the dielectrlcal• layer possesses the ordinary properties of t.he '.ieleotrical gra-' inns, i.e. the properties cf the energysfiver end oi the focal action on the field. The presence Of the layer tends to increment these effcotn. ' ; •'•

Some gei.^ral ' Jiaturalities öf the- wave propagation -into complicated electrodynanic structures aro also determined: ,

a) The properties of complicated electrodynamie structures combiae the properties of oil the elementj of the sis-em,' tak'ng Jjito account tve diffraction interaction -botween theOi -

b) in the tlll-dlitfractional region (in the case of lor» waves) the properties of.the ei3tem practically don't depend- , on the grating parametres and depend only an the gratiug , ■ *. e^empritB material and on the polarization of. the falling, wave;' , ; ■. ; .-.'«' — • v »,.'■•'

Electromagnetic Diffraction

c) In the one-wave region (for the ' semitran3parent gratings) ' ¿he reaonan3e effecca of the . totrl passing and refiecti'i of the falling wave.are seen! the presence of thö additional elements tends to increment these effects;

Diffraction Electromagnetic Waves

d) In the mul' lwave region the transformation of tha main wave into the higher types of waves.is seen; at this time in

'near zone the giant energy whirlwinds, . taking the most part of the gratl' g period, are formed; .5,.: :

e) To vary the .system parometres, is..possible to get the r rder properties bf -thp BystfB in -¡.be far ai.d. the near Bones. :

Approbation _of _ the__«ork. The ^resulwE received * on the i jpärätö st^es of tiie disnertiitioD preparation were declared -on the All-Onion simposium on ¿iffruction L.nd propagation of wavi3 (Telavi, .1985), on the /ll-Ouion scientific conference on volumed integral schemes (Moscow, 1Ü87), andon oeuinars of the Department of General Physios andRndiophyBius ot Georgian Technical University;.' . ..v ' ' ' 1 .','.-*,•

Publications of the dissertation theme are'reduced at the end of't;ie abrtraot. -'•'.■.-.' - >V .

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г. Кевэншвила Р.Г. Рассеяние плоской волны на системе из решетки и экрана. Труды^ШИ - Дифракция электромагнитных волн, • IS86, Ii 5(302), с. 27-29.' . Богданов Ф.Г., Кеванишвили Р.Г. Отражение плоской волан от идеально проводящего экрана и решетки из металлических цилиндров. -Дел. в ВИШИ. 20.I7.I9S7. № ¿$44-Ш7'. Кеванишвили Р.Г., Кекалия В.Л. Нормальное падение плоской. В-поляризованной волны на систему, .из диэлектрического слоя и диэлектрической решетки - Дифракция электромагнитных волн /Труды ЛШ 1986г. № 302, с.51-57/ ' _ ' ..

:. Богданов Ф.Г., Кеванишвили Р.Г. и др. Дифракция электромагнрт-' ных волн на решетке из диэлектрических цилиндров в диэлекгрв-часком слое.'Труды НУ, Физика, Л 22(265), с.33-47.

>. Богданов Ф.Г., Кеванишвили Г.Ш., Кеванишвили Р.Г. и др. Рассея-' ние плоских электромагнитных волн на системах из диэлектрического слоя и круглоцилиндрическах решеток. Волны а дифракция, Т.П., 1985 (с.201-204)]текст доклада (IX Всесоюзный симпозиум по дифракции а распространению) ........

». Богданов Ф.Г., Кеванишвили Г.Ш.,.Кеванишвили ?.Г, Медзиариа-твила Э.В. . Влияние проволочного.каркаса «защитных укрытий на электрические характеристики, осе симметричных, антенн СВЧ. Антенны (сб.статьей, вып.37, Москва 'Радио и связью, 1990, стр.87-96.